99 



wards along the ridges radiating from it, is scarcely notice- 

 able to the eye. The Dome is the principal drainage centre 

 of the district. From it, Allgold and Dominion creeks 

 flow eastward, Quartz and Sulphur creeks southward, and 

 Goldbottom and Hunker northward. The ridges separat- 

 ing these streams, although deeply and repeatedly gashed 

 by tributary valleys, are unbroken, and it is possible, start- 

 ing from the Dome, to reach any part of the district with- 

 out descending into the valleys. Subordinate drainage 

 centres occur at other places. 



General Geology. 



Klondike district is underlain by a complex of rock 

 formations ranging in age through the greater part of the 

 geological scale and presenting extreme variety in structure 

 and composition. The region has been repeatedly 

 broken through by igneous intrusions at widely separated 

 periods, and has been subjected to enormous pressure from 

 earth movements. Alterations in the character of the 

 rocks, induced by dynamic and associated metamorphic 

 agencies, have proceeded to an extreme degree. Massive 

 igneous rocks have been sheared and crushed into finely 

 foliated schists, and the elastics in many places recrystal- 

 ized to the semblance of igneous rocks. The oldest and 

 most important formations consist of ancient schists, part- 

 ly of clastic and partly of igneous origin. 



The southern part of the district is underlaid by 

 altered sedimentary rocks, now represented dominantly 

 by quartz-mica-schists and crystalline limestones. These 

 are bordered on the north by a wide band of light-coloured, 

 in places almost white, sericite-schists alternating occasion- 

 ally with greenish chloritic schists. All these various 

 types of schists have been derived from igneous, and largely 

 from massive igneous rocks. The principal producing 

 creeks of Klondike district occur in the area occupied by 

 them. The sericite-schists and associated rocks are 

 replaced near the mouth of Klondike river by green diabase 

 rocks, which are usually schistose in structure, but in places 

 might almost be termed massive. These diabase rocks 

 are everywhere greatly altered and, on Moosehide mountain 

 pass into serpentine. East of the diabase and serpentine 

 area on Moosehide mountain, the sericite-schists alternate 

 on the north with bands of dark quartz-mica-schists, very 

 similar to those bordering them on the north. 

 34883—7^ 



